The following abbreviations, at least some of which appear in the description below, are defined as follows:    3GPP Third Generation Partnership Project    ARQ Automatic Repeat Request    BTS Base Transceiver Station    CFN Connection Frame Number    CPICH Common Pilot Channel    DL Downlink    DPCH Dedicated Physical Channel    F-DPCH Fractional Dedicated Physical Channel    H-ARQ Hybrid ARQ    HSDPA High-Speed Downlink Packet Access    HS-DPCCH High-Speed Dedicated Physical Control Channel    HS-DSCH High-Speed Downlink Shared Channel    HS-PDSCH High-Speed Physical Downlink Shared Channel    HS-SCCH High-Speed Shared Control Channel    MAC Medium Access Control    RLC Radio Link Control    RNC Radio Network Controller    RNTI Radio Network Temporary Identifier    RRC Radio Resource Control    SHO Soft Handover    SRB Signaling Radio Bearer    SIR Signal to Interference Ratio    TPC Transmit Power Control    TTI Transmission Time Interval    UE User Equipment    UL Uplink    UMTS Universal Mobile Telecommunications System C304    UTRA-FDD UMTS Terrestrial Radio Access-Frequency Division Duplex    UTRAN UMTS Terrestrial Radio Access Network    VoIP Voice Over Internet Protocol    WCDMA Wideband Code Division Multiple Access
The DL packet data transmission in UTRA FDD (WCDMA) is a feature included in Release 6 of the 3GPP TS 25.214 technical specification with the support of fractional DPCH (F-DPCH), and with the support of SRB mapping on the HS-DSCH.
In order to reduce the code usage when HSDPA is deployed, the Fractional DPCH was introduced. With the F-DPCH, a new quality target for generating downlink power control commands by the UE is specified. More specifically, when the Fractional DPCH (F-DPCH) concept was originally approved it was decided that generating DL power control commands should be based on a quality target that uses a downlink TPC command error rate target value for F-DPCH. However, the issue of whether the quality criterion should be satisfied for all radio links when in SHO was left for further study.
One prior proposal in this area (R1-050098 F-DPCH Downlink Power Control, Ericsson) involves meeting the quality target for all radio links in the active set. However, this can lead to excessive power being used for transmitting F-DPCH. In large active sets some of the cells are typically not detectable, and fulfilling the quality criteria for the undetectable cell or cells will unnecessarily cause an increase in the power of the detectable cells.